/*********************************************************************
 * Copyright (C) 2002 Andrew Khan
 * <p>
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * <p>
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * <p>
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ***************************************************************************/

package jxl.biff.formula;

import jxl.WorkbookSettings;
import jxl.biff.IntegerHelper;
import jxl.common.Assert;
import jxl.common.Logger;

import java.util.Stack;

/**
 * A built in function in a formula
 */
class BuiltInFunction extends Operator implements ParsedThing {
    /**
     * The logger
     */
    private static Logger logger = Logger.getLogger(BuiltInFunction.class);

    /**
     * The function
     */
    private Function function;

    /**
     * The workbook settings
     */
    private WorkbookSettings settings;

    /**
     * Constructor
     * @param ws the workbook settings
     */
    public BuiltInFunction(WorkbookSettings ws) {
        settings = ws;
    }

    /**
     * Constructor used when parsing a formula from a string
     *
     * @param f the function
     * @param ws the workbook settings
     */
    public BuiltInFunction(Function f, WorkbookSettings ws) {
        function = f;
        settings = ws;
    }

    /**
     * Reads the ptg data from the array starting at the specified position
     *
     * @param data the RPN array
     * @param pos the current position in the array, excluding the ptg identifier
     * @return the number of bytes read
     */
    public int read(byte[] data, int pos) {
        int index = IntegerHelper.getInt(data[pos], data[pos + 1]);
        function = Function.getFunction(index);
        Assert.verify(function != Function.UNKNOWN, "function code " + index);
        return 2;
    }

    /**
     * Gets the operands for this operator from the stack
     *
     * @param s the token stack
     */
    public void getOperands(Stack s) {
        // parameters are in the correct order, god damn them
        ParseItem[] items = new ParseItem[function.getNumArgs()];
        // modified in 2.4.3
        for (int i = function.getNumArgs() - 1; i >= 0; i--) {
            ParseItem pi = (ParseItem) s.pop();

            items[i] = pi;
        }

        for (int i = 0; i < function.getNumArgs(); i++) {
            add(items[i]);
        }
    }

    /**
     * Gets the string for this functions
     *
     * @param buf the buffer to append
     */
    public void getString(StringBuffer buf) {
        buf.append(function.getName(settings));
        buf.append('(');

        int numArgs = function.getNumArgs();

        if (numArgs > 0) {
            ParseItem[] operands = getOperands();

            // arguments are in the same order they were specified
            operands[0].getString(buf);

            for (int i = 1; i < numArgs; i++) {
                buf.append(',');
                operands[i].getString(buf);
            }
        }

        buf.append(')');
    }

    /**
     * Adjusts all the relative cell references in this formula by the
     * amount specified.  Used when copying formulas
     *
     * @param colAdjust the amount to add on to each relative cell reference
     * @param rowAdjust the amount to add on to each relative row reference
     */
    public void adjustRelativeCellReferences(int colAdjust, int rowAdjust) {
        ParseItem[] operands = getOperands();

        for (int i = 0; i < operands.length; i++) {
            operands[i].adjustRelativeCellReferences(colAdjust, rowAdjust);
        }
    }

    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex the sheet on which the column was inserted
     * @param col the column number which was inserted
     * @param currentSheet TRUE if this formula is on the sheet in which the
     * column was inserted, FALSE otherwise
     */
    void columnInserted(int sheetIndex, int col, boolean currentSheet) {
        ParseItem[] operands = getOperands();
        for (int i = 0; i < operands.length; i++) {
            operands[i].columnInserted(sheetIndex, col, currentSheet);
        }
    }

    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex the sheet on which the column was removed
     * @param col the column number which was removed
     * @param currentSheet TRUE if this formula is on the sheet in which the
     * column was inserted, FALSE otherwise
     */
    void columnRemoved(int sheetIndex, int col, boolean currentSheet) {
        ParseItem[] operands = getOperands();
        for (int i = 0; i < operands.length; i++) {
            operands[i].columnRemoved(sheetIndex, col, currentSheet);
        }
    }


    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex the sheet on which the row was inserted
     * @param row the row number which was inserted
     * @param currentSheet TRUE if this formula is on the sheet in which the
     * column was inserted, FALSE otherwise
     */
    void rowInserted(int sheetIndex, int row, boolean currentSheet) {
        ParseItem[] operands = getOperands();
        for (int i = 0; i < operands.length; i++) {
            operands[i].rowInserted(sheetIndex, row, currentSheet);
        }
    }

    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex the sheet on which the row was removed
     * @param row the row number which was removed
     * @param currentSheet TRUE if this formula is on the sheet in which the
     * column was inserted, FALSE otherwise
     */
    void rowRemoved(int sheetIndex, int row, boolean currentSheet) {
        ParseItem[] operands = getOperands();
        for (int i = 0; i < operands.length; i++) {
            operands[i].rowRemoved(sheetIndex, row, currentSheet);
        }
    }

    /**
     * If this formula was on an imported sheet, check that
     * cell references to another sheet are warned appropriately
     * Does nothing, as operators don't have cell references
     */
    void handleImportedCellReferences() {
        ParseItem[] operands = getOperands();
        for (int i = 0; i < operands.length; i++) {
            operands[i].handleImportedCellReferences();
        }
    }

    /**
     * Gets the token representation of this item in RPN
     *
     * @return the bytes applicable to this formula
     */
    byte[] getBytes() {
        // Get the data for the operands
        ParseItem[] operands = getOperands();
        byte[] data = new byte[0];

        for (int i = 0; i < operands.length; i++) {
            byte[] opdata = operands[i].getBytes();

            // Grow the array
            byte[] newdata = new byte[data.length + opdata.length];
            System.arraycopy(data, 0, newdata, 0, data.length);
            System.arraycopy(opdata, 0, newdata, data.length, opdata.length);
            data = newdata;
        }

        // Add on the operator byte
        byte[] newdata = new byte[data.length + 3];
        System.arraycopy(data, 0, newdata, 0, data.length);
        newdata[data.length] = !useAlternateCode() ? Token.FUNCTION.getCode() :
                Token.FUNCTION.getCode2();
        IntegerHelper.getTwoBytes(function.getCode(), newdata, data.length + 1);

        return newdata;
    }

    /**
     * Gets the precedence for this operator.  Operator precedents run from
     * 1 to 5, one being the highest, 5 being the lowest
     *
     * @return the operator precedence
     */
    int getPrecedence() {
        return 3;
    }
}

